JP2012017017A - Twin-skeg ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twin-skeg ship, which reduces a ship resistance caused by the vortex drag of a pair of right and left skegs, and improves the propeller propulsive efficiency.SOLUTION: The twin-skeg ship 1 includes a guide 8 for guiding a longitudinal vortex S occurring on the inner side in the ship board direction of each skeg 5 toward the hull center CL side, in each of the inner side surfaces in the ship board direction of each skeg 5. The guide is formed in the inner side surface in the ship board direction at a lower end of each of the skegs, whose thickness in the vertical direction may be formed into a projection that is shaped thinner from the outer side to the inner side in the ship board direction.

Description

  The present invention relates to a twin-skeg ship provided with a pair of left and right skeg portions that are provided at the stern portion at an interval in the stern direction and each support a propeller shaft, and a pair of left and right propellers that are respectively attached to the stern side ends of the propeller shaft. .

  As a stern shape of a biaxial ship having a pair of left and right propellers at the stern part, there is a so-called twin skeg hull form in which a pair of saddle-like skeg parts covering the propeller shaft are provided at the stern part of the hull. Such a twin-skeg ship having a twin-skeg hull form is also described, for example, in Patent Document 1.

JP 2008-247322 A

  Usually, in a skeg ship (uniaxial ship), a pair of left and right vertical vortices (stern vertical vortices) are generated at the stern. On the other hand, in a twin skeg ship, since there are a pair of left and right skeg parts at the stern part, a total of four vertical vortices are generated at the stern part. Therefore, in a twin-skeg ship, hull resistance due to vortex resistance increases, and the propulsion performance may be reduced.

  Therefore, an object of the present invention is to cancel or weaken a pair of vertical vortices generated on the inner side of the pair of left and right skeg portions, thereby reducing the hull resistance due to the vortex resistance, and the ridge direction of the pair of left and right skeg portions. The propulsion propulsion efficiency (propeller rotation efficiency) is improved by collecting the rotational energy of a pair of vertical vortices generated on the outside with a pair of left and right propellers, thereby improving the propulsion performance of the twin-skeg ship.

  In order to achieve the above object, the present invention is provided at the stern portion with a gap in the stern direction, and is attached to a pair of left and right skeg portions that respectively support the propeller shaft, and a stern side end of the propeller shaft. In a twin skeg ship provided with a pair of left and right propellers, a guide part is provided on the inner side surface of each skeg part in the ship direction so as to guide the vertical vortex generated on the inner side in the ship direction to each hull direction.

  The guide portion may be formed of a protruding portion that is formed on an inner side surface in a boat direction at a lower end portion of each skeg portion, and whose thickness in the vertical direction becomes thinner from the outer side in the boat direction toward the inner side in the boat direction.

  The guide portion may be a fin that is attached to the inner surface in the boat direction at the lower end of each of the skeg portions, and that protrudes inward in the boat direction.

  The rotation direction of each propeller may be set in the direction opposite to the rotation direction of the vertical vortex generated on the outer side in the ship direction of each skeg portion.

  According to the present invention, by canceling or weakening a pair of vertical vortices generated on the inner side of the pair of left and right skeg portions, the hull resistance due to the vortex resistance is reduced, and on the outer side of the pair of left and right skeg portions in the ship direction. By collecting the rotational energy of the pair of vertical vortices generated by a pair of left and right propellers, the propeller propulsion efficiency (propeller rotation efficiency) can be improved and the propulsion performance of the twin-skeg ship can be improved. Play.

FIG. 1A is a rear view (contour diagram of a hull transverse cross section) of a twin-skeg ship according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA in FIG. . FIG. 2A is a rear view of a twin-skeg ship according to another embodiment (contour diagram of a cross section of a hull), and FIG. 2B is a cross-sectional view taken along line BB in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, a twin skeg ship 1 according to this embodiment is provided with a pair of left and right skeg parts 5 that are provided at a stern part 3 of a hull 2 with a space in the stern direction and respectively support a propeller shaft 4. A tunnel-shaped bottom bottom recess 6 formed between the pair of skeg portions 5, a pair of left and right propellers 7 respectively mounted on the stern side ends of the propeller shaft 4, and the stern portion 3 are positioned on the stern side of the propeller 7. A pair of left and right rudders (not shown) are provided. In addition, illustration of the propeller 7 is abbreviate | omitted in Fig.1 (a).

  The skeg portion 5 extends downward from the bottom of the stern portion 3 and is formed so that the width in the boatway direction becomes narrower from the bow side toward the stern side (see FIG. 1A). The skeg portion 5 supports the propeller shaft 4 at an intermediate portion in the height direction.

  The tunnel-shaped bottom bottom recess 6 is formed such that the ceiling surface 6a becomes higher from the bow side toward the stern side. That is, the bottom portion of the stern portion 3 between the pair of left and right skeg portions 5 is formed so as to become higher from the bow side toward the stern side.

  The propeller 7 is driven via the propeller shaft 4 by a driving device (not shown).

  The rudder is driven by a steering device (not shown).

  In the twin skeg ship 1 according to the present embodiment, guide portions 8 are provided on the inner side surface of the pair of left and right skeg portions 5 to guide the vertical vortex S generated on the inner side of the skeg portion 5 toward the hull center CL. Yes. The guide portion 8 of the present embodiment is formed on the inner side surface in the boat direction at the lower end portion of the skeg portion 5, and includes a protruding portion 9 whose vertical thickness becomes thinner from the outer side in the boat direction toward the inner side in the boat direction. In other words, the protrusion 9 has a corner 9a facing the inner side in the boat direction (see FIG. 1A).

  In the present embodiment, the protruding portion 9 is formed integrally with the lower end portion of the skeg portion 5. Further, the protruding portion 9 extends from the bow side end portion of the skeg portion 5 to the stern side end portion (see FIG. 1 (b)), and the corner 9a is located on the inner side in the vessel direction as it goes from the bow side to the stern side. It is formed (see FIG. 1A).

  Further, in the twin skeg ship 1 according to the present embodiment, the rotation direction X of the propeller 7 (see FIG. 1A) is set in the direction opposite to the rotation direction of the vertical vortex S generated outside the ship side of the skeg part 5. ing. Specifically, since the rotation direction of the vertical vortex S generated on the port side of the skeg portion 5 on the port side is clockwise (clockwise) in the rear view, the port side propeller 7 is counterclockwise in the rear view. Since the rotation direction of the longitudinal vortex S that is rotated (counterclockwise) and is generated on the starboard side of the skeg portion 5 outward in the boat direction is counterclockwise (counterclockwise) when viewed from the rear, the starboard side propeller 7 is viewed from the rear To rotate clockwise (clockwise). That is, the pair of left and right propellers 7 are rotated outward from each other.

  The operation of this embodiment will be described.

  Since the generation position of the vertical vortex S is determined by the separation point of the flow from the stern section 3, the generation position of the vertical vortex S can be controlled by devising the shape of the stern section 3. Further, when the reversely rotating vertical vortices S are superposed, the vertical vortices S can be canceled or weakened.

  As described above, the protrusion 9 having the corner 9a is formed on the inner side surface of the skeg portion 5 in the ship direction, and the vertical vortex S is generated from the corner 9a of the protrusion 9 so that the pair of left and right skeg portions 5 in the ship direction. The vertical vortex S generated on the inner side in the ship's direction of the skeg portion 5 is guided to a position where the pair of counter-rotating vertical vortices S generated on the inside overlap and cancel each other (that is, the hull center CL side).

  That is, in a general twin-skeg ship, the vertical vortex is generated from the lower end of the skeg part. However, in the twin-skeg ship 1 according to the present embodiment, the protruding part 9 having the corner 9a is formed on the inner side surface of the skeg part 5 in the ship direction. Therefore, the protruding portion 9 becomes a generation point of the vertical vortex S generated on the inner side of the skeg portion 5 in the ship direction.

  As a result, a pair of counter-rotating vertical vortices S generated on the inner side of the pair of left and right skeg portions 5 overlap and cancel each other on the hull center CL side, and a pair of vertical vortices S generated on the outer side of the skeg portion 5 in the ship direction. Since only remains, hull resistance due to eddy resistance is reduced.

  Further, by rotating the propeller 7 in the direction opposite to the rotation direction of the remaining vertical vortex S (vertical vortex S generated on the outer side of the skeg portion 5 in the ship direction), the remaining vertical vortex S (the outer side of the skeg portion 5 in the ship direction) is further rotated. Since the rotational energy of the vertical vortex S) generated in is recovered by the propeller 7, the rotation efficiency of the propeller 7 can be improved.

  In short, according to the present embodiment, in order to cancel and weaken the pair of vertical vortices S generated on the inner side of the pair of left and right skeg parts 5 in the ship direction, each skeg part is provided on the inner side surface of each skeg part 5 in the ship direction. 5 is provided with a guide portion 8 (protrusion portion 9) for guiding the vertical vortex S generated on the inner side in the ship direction to the hull center CL side, and a pair of vertical vortices S generated on the outer side in the ship direction of the pair of left and right skeg portions 5 In order to improve the rotation efficiency of the pair of left and right propellers 7 by the rotational energy, the rotation direction X of each propeller 7 is set in the opposite direction to the rotation direction of the vertical vortex S generated outside the ship direction of each skeg portion 5. By canceling or weakening the pair of longitudinal vortices S generated on the inner side of the pair of left and right skeg portions 5, the hull resistance due to the vortex resistance is reduced, and the one generated on the outer side of the pair of left and right skeg portions 5 in the ship direction. The rotational energy of the longitudinal vortex S by collecting in a pair of left and right propellers 7, to improve the propeller propulsion efficiency (rotation efficiency of the propeller 7), it is possible to improve the propulsion performance of Tsuinsukegu ship 1.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various other embodiments can be adopted.

  For example, as shown in FIG. 2, instead of forming a protrusion 9 having a corner 9 a on the inner side surface in the boat direction at the lower end portion of the skeg portion 5, fins (flat plates) are provided on the inner surface in the boat direction at the lower end portion in the skeg portion 5. ) Even if 10 is provided, the same effect as the above embodiment can be obtained. That is, the guide portion 8 may be composed of the fin 10. In FIG. 2, the fin 10 is provided in the lower end of the skeg part 5 so that it may protrude in a horizontal direction. Further, the fin 10 extends from the bow side end of the skeg portion 5 to the stern side end (see FIG. 2 (b)), and the tip 10a is formed so as to be located on the inner side in the ship side as it goes from the bow side to the stern side. (See FIG. 2 (b)).

  Further, the guide portion 8 (projection portion 9, fin 10) may extend from the stern portion intermediate portion of the skeg portion 5 to the stern side end portion.

1 Twin Skeg Ship 3 Stern 4 Propeller Shaft 5 Skeg 7 Propeller 8 Guide 9 Protrusion 10 Fin (Plate)
CL hull center

Claims (4)

  In a twin skeg ship provided with a pair of left and right skeg portions that are provided at intervals in the stern portion at the stern portion and each support a propeller shaft, and a pair of left and right propellers that are respectively attached to the stern side ends of the propeller shaft, A twin skeg ship, characterized in that a guide part for guiding a vertical vortex generated on the inner side in the ship direction of each skeg part to the ship center side is provided on the inner side surface of each skeg part in the ship direction.   2. The twin-skeg ship according to claim 1, wherein the guide part is formed on a shipboard inner side surface at a lower end part of each skeg part, and includes a protrusion part whose thickness in the vertical direction becomes thinner from the shipboard direction outer side toward the shipboard direction inner side.   2. The twin skeg ship according to claim 1, wherein the guide part is a fin attached to an inner side surface in a ship direction at a lower end portion of each of the skeg parts and extending to an inner side in the ship direction.   2. The twin skeg ship according to claim 1, wherein the rotation direction of each propeller is set to be opposite to the rotation direction of a vertical vortex generated outside the ship direction of each skeg part.

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